Container lid and method for making same

ABSTRACT

A method and apparatus for making a container lug lid which minimizes scrap waste is described. The blanks for forming container lug lids therefrom comprise an odd number of dissimilar lugs with one or more of the lugs comprising a male lug. Circumferential bases are formed between each lug, with one or more of the circumferential bases having a female complementary shape for receiving a male lug of an adjacent blank. The blank pattern for cutting the blanks from a sheet of material, which is preferably scrolled, comprises arranging the blanks in a closely spaced arrangement with the male lugs positioned for alignment with an adjacent female or complementary shaped circumferential base.

FIELD OF THE INVENTION

The present invention pertains generally to lid closures for use withcylindrical containers. More particularly, the invention pertains tometal lid closures having a plurality of lugs which are crimped forclosing and sealing the ends of a pail or container, and to a method formaking the same.

BACKGROUND OF THE INVENTION

Many types of prior art container lids have been devised for closingpails or containers. These container lids are generally applied to anopen ended pail or container which has a curled annular rim formed aboutan open end. Prior art lids are generally disc-shaped and have adownwardly facing annular groove or channel adapted to receive theannular rim of the container. A series of lid lugs project downwardlyfrom the annular channel of the lid for attaching the lid to thecontainer rim. For example, lug lids for use with two and one half toseven gallon containers generally contain an even number of lugs on theorder of 16 to 20 lugs, which are formed along a circumferential edge ofthe lid with spaces formed between the lugs. The lid is sealed to thecontainer by use of a crimping tool to crimp the lugs about the annularrim of the container in a sealing arrangement.

These metal container lids are generally manufactured by blanking orpunching a rectangular or square sheet of metal with a patterncomprising a plurality of unfolded container lids or blanks. Forexample, a typical prior art punch pattern is shown in FIG. 1, andcomprises four closely spaced unfolded container lids which aresymmetrical in shape. One major disadvantage of the prior art containerlid design and punch pattern is that costly material is wasted inbetween the holes (i.e., the scrap skeleton) even though the blanks areclosely spaced together. In addition, a larger sheet of material isrequired than necessary in order to produce a given number of containerlids. This waste is a function of the container lid design and theamount of spacing allotted for adjacent blanks. Scrap materialrepresents an expensive loss which is only partly recoverable and whichrequires additional resources to convert into a usable form. Anotherdisadvantage of the prior art is that more time is wasted in gatheringand transporting the scrap to recycling centers. Yet anotherdisadvantage of the prior art is that paint used to coat the sheet priorto punching is wasted as well as the additional energy required to curethe paint on a larger sheet.

It is therefore desirable to provide an improved container lid designand blank pattern layout which reduces the amount of scrap materialgenerated and thus results in considerable cost savings with very fewdrawbacks. It is further desirable to provide an improved container liddesign and blank pattern layout which reduces the sheet size of thematerial while producing an equivalent number of lids.

SUMMARY OF THE INVENTION

In accordance with the teaching of this invention a container lid isprovided, together with a process for making the same in which thecontainer lid is capable of being inexpensively manufactured withminimal material waste being generated and while having the advantagesenjoyed by prior art container lids.

The invention provides in one aspect a lug lid for sealing a containerhaving an annular curved rim, the lug lid comprising a planar surfacehaving an annular channel on the peripheral edge of said lid; aplurality of lugs projecting downwardly from an outer wall of thechannel; one or more of said lugs being asymmetrically shaped relativeto the other lugs; and a plurality of circumferential bases formedbetween adjacent lugs.

The lug lid provides in another aspect a lug lid comprising a planarsurface having an annular channel on a peripheral edge of said lid; anodd number of lugs projecting from an outer wall of the channel with oneor more of said lugs comprising a male lug; and a plurality ofcircumferential bases formed between adjacent lugs with one or more ofsaid circumferential bases comprising a female mating gap.

The lug lid provides in yet another aspect of the invention an oddnumber of lid lugs having at least some of those lugs formed in adifferent shape than other lugs on that lid. The ends of the lugs maybebent or curled to facilitate removal of the lid from the container.

The invention provides in another aspect a method for making a pluralityof container lids comprising the steps of forming one or more lidblanks, each blank comprising a plurality of lugs on a peripheral edgeof said blanks, a plurality of circumferential bases formed between eachof said lugs, one or more of said lugs comprising a male lug, and one ormore of said circumferential bases having a complementary female shapefor mating with said male lug; arranging the lid blanks upon a sheet ofmaterial such that each of said male lug of an adjacent lid blank isaligned and positioned within said mating circumferential base of anadjacent lid blank; cutting the lid blanks from a sheet of material; andforming a container lid from each of said blanks.

The invention provides in yet another aspect a method for makingcontainer lids comprising the steps of: forming two or more lid blankshaving a plurality of lugs on the peripheral edge of the blank, with aplurality of circumferential bases formed between each of said lugs,arranging the lid blanks upon said sheet of material such that one ormore of said lugs of a lid blank are interlocked with respect to lugs ofan adjacent blank; cutting a plurality of lid blanks from a sheet ofmaterial; and forming a container lid from each of said blanks.

The invention provides in still another aspect a container lid preparedby the method comprising the steps of forming a plurality of lid blanks,each said blank comprising a plurality of lugs on a peripheral edge ofsaid lid, a plurality of circumferential bases formed between each ofsaid lugs, one or more of said lugs comprising a male lug, and one ormore of said circumferential bases having a complementary shape formating with said male lug; arranging the lid blanks patterns upon asheet of material such that said male lug of an adjacent lid blank ispositioned within said complementary shaped circumferential base of anadjacent lid blank; cutting the arranged lid blanks from a sheet ofmaterial; and forming a container lid from each of said blanks.

The method in another aspect of the invention utilizes a speciallyconfigured sheet of material designed in conjunction with theconfiguration of the lid blanks substantially to maximize utilization ofthe sheet material. In one form, the sheet material has rectangularaligned end sections with an offset center portion, the offset beingformed by a trapezoid of material being added to and extending outwardlyfrom one margin of the sheet while a trapezoidal recess of the same sizeand shape is provided on the other margin. This material shape permitsat least three rows of lid blanks to be positioned on the material, withthe center row offset from the top and bottom rows to permit adjacentlug blanks in the rows to be more closely spaced to one another.

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

FIG. 1 is a plan view of the prior art scroll layout of container lidblanks;

FIG. 2 is a perspective view of the container lid design of the presentinvention adapted to be received on a prior art container;

FIG. 2A is a perspective view of a portion of the container lid designshowing the other side of the lid in FIG. 1;

FIG. 3 is a cross section of the container lid of the present inventiontaken in the plane 2--2 as shown in FIG. 1;

FIG. 4 is a plan view of the layout of container lid blanks of thepresent invention;

FIG. 5 is a plan view of a single container lid blank of the invention;

FIG. 6 is a greatly enlarged portion of FIG. 4 showing the interface ofmating lugs of adjacent container blanks;

FIG. 7 is a plan view of an alternative embodiment of the pattern layoutof container lid blanks of the present invention; and

FIG. 8 is a plan view of an alternative embodiment of the pattern layoutof container lid blanks of the present invention.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

With reference to the Figures, and more particularly to FIGS. 2 through3, there is illustrated a new and improved container lid 10 for use inconjunction with prior art containers 20 typically made of plastic ormetal. These prior art containers 20 are suitable for the storage andtransportation of paint, liquids, and other flowable materials in asealed airtight condition. These prior art containers or buckets 20 aregenerally formed from steel sheets or other resilient material andcomprise a cylindrical container body 22 having sidewalls, aconventional closed lower end (not shown), and an open upper end 24which cooperate to define a storage chamber. The open upper end 24generally has a curled annular rim 26 which is formed from a curl ofrolled metal or other suitable material and is adapted to receive a luglid 10.

The lug lid 10 of the invention generally comprises a planar surface 30preferably having a circular or disk-like shape having a plurality ofannular strengthening ribs 11 and an annular downwardly facing channel32 comprising a raised and inverted U-shaped cross section forming anouter peripheral edge 34 of the lug lid 10. The annular channel 32 isadapted to fit over and seat upon the annular rim 26 of the container20, with the annular rim 26 being received in the annular recess of thechannel 32. An optional gasket (not shown) may be seated and affixed byconventional means in the annular channel. Once the lid 10 is seatedupon the container rim, a plurality of lugs 40 are crimped along theannular rim 26 of the container 20 such that the lid is in sealingengagement with the container 20.

The lugs 40 are formed about the periphery of the lug lid 10, projectingdownwardly from an outer wall 42 of the annular channel 32. The lug lid10 of the invention preferably has an odd number of lugs 40, typicallyin the range of 13 to 17, and preferably 15 lugs, many of which areuniquely shape. In contrast, prior art lug configurations (not shown)generally provide an even number of identically shaped lugs, on theorder of 18 to 20 lugs per lid. The lugs 40 of the invention overlap therim 26 of the container 20 when the lid 10 is seated upon the rim 26.The shapes of most of the lugs 40 generally are rectangular with curvedor rounded edges 43 terminating in a flat edge 44. However, many otherlug shapes would work for the invention. An optional tabular end 45 maybe formed on the flat edge 44, which may be formed or bent into anupward curl 46 in order to facilitate opening of the crimped lugs 40.The optional curl 46 may be utilized to pry the crimped lugs open inorder to release the lid 10. Interspaced between each of the lugs 40 arecircumferential bases 48 which exist between each lug 40 in order toassist in the crimping of the lugs around the rim curl 26 of thecontainer 20.

In contrast to the prior art however, not all of the lugs 40 areidentical in shape. Almost all of the lugs 40 have different shapes andvarying widths. As shown in FIG. 5, the blank lid design 50 has oneplane of symmetry 52 due to the odd number of lugs and the unique shapeof each lug. Beginning with lug 54 in the 9 o'clock position, lug 54 hasa curved edge 43, a tabular end 45 and a truncated upper edge 55connected to an elongated circumferential base 56 formed between lug 60and lug 54. A truncated edge 58 of lug 60 is connected to the elongatedcircumferential base 56 formed between lug 60 and lug 54. Thesetruncated edges 55,58 in combination with the elongated circumferentialbase 56 form a female mating base 51 which is used to facilitate theinterlocking of the lid blanks 50 as shown in FIG. 4, and as explainedin more detail, below. The design of lug 60 is thus the mirror image oflug 54, each of which further comprises a tabular end 45 connected tothe truncated edge 55,58 and a rounded end 43 adjoining the tabular end45.

Lugs 64, 68, 72, 76 and 80 are all very similarly shaped as a rectanglewith rounded or radiused edges 43 with a tabular end 45 formed on theouter peripheral edge. Formed between adjoining lugs are circumferentialbases 48 of varying widths. Lugs 64 and 68 are slightly canted towardseach other, while lugs 76 and 80 are canted away from each other suchthat interdigitization is facilitated, as explained in more detail,below. Lug 84 is also approximately rectangular in shape with a radiusededge 43 on one end and a edge 85 that is partially radiused andpartially truncated closest to the circumferential base formed betweenlugs 84 and 88. Lug 88 is pyramidal in shape, i.e., two inclined edges89 joined to a circumferential edge 90 there between and forming a malelug for production purposes. Lugs 94 through 114 because of the plane ofsymmetry, are the mirror image of lugs 84 through 60, respectively. Forexample, lug 94 is the mirror image of lug 84, lug 98 is the mirrorimage of lug 80, etc.

The punching pattern of conventional lid blanks as shown in FIG. 1demonstrates that the container lid blanks are sufficiently spaced apartsuch that the blanks do not touch each other at any place and aredisposed about the same distance from each other. Punching out the lidsfrom the material therefore necessarily results in the production of aresidual punching grid or scrap skeleton which can be utilized only asscrap. Moreover, for a given lid size, a larger material surface area isrequired for the same number of container lids for the prior art designas compared to the design and layout of the invention.

FIG. 4 shows the punching pattern of six container lid blanks 50 of theinvention from a scrolled sheet of metal. FIG. 4 illustrates three rowsof container lid blanks comprised of 2 lid blanks in each row, with thecenter row being offset from the top and bottom rows. In each row, themale lug 88 of the container lid blank is aligned with, and placedbetween the female circumferential base 51 formed between the lugs ofthe adjacent container lid blank, leaving a very thin scrap skeleton asshown in FIG. 6. The container lid blank lugs in the adjacent rows arealigned with and placed closely between the circumferential bases of theadjoining container lid blanks. Thus the container lid lugs areinterdigitated or interlocked with the lugs in the adjacent rows,analogous to gear teeth between mating gears.

This relationship between the respective lid blanks and lid rowsminimizes the amount of material between the lid blanks and thusminimizes the scrap skeleton remaining when the lids have been removedfrom the sheet material. The design of the odd number of speciallyconfigured lid lugs, the layout of the lid blanks and offset lid blankrows and the shape of the sheet material contribute to the efficiency ofthe process. In the preferred form the scrolled sheet material,indicated generally at 120, has two rectangular ends 122 and 124 and anoffset central section, indicated generally at 126. The offset centralsection 126 is formed by a trapezoidal piece 128 being added to andextending outwardly from one side or margin of sheet material 120 and asimilarly shaped and sided trapezoidal recess 130 being provided on theother side.

In an alternative embodiment of the invention, the container lid blank50 may comprise three or more female circumferential bases 51 and threeor more male shaped lugs 88, such as shown in FIG. 7. The male lugs 88and the female circumferential bases 51 are alternated on a containerlid blank 50. Thus as shown, the layout of the container blanks 50 inthe middle row are such that the female circumferential bases 51 and themale lugs 88 are positioned for alignment with the adjacent male lugs 88and female circumferential bases 51.

In yet another alternative embodiment of the invention as shown in FIG.8, the container lid blank 140 comprises an odd number of symmetricallyshaped lugs 143 with circumferential bases 144 formed between each lug.Preferably, the blank has 15 lugs, with each lug having the same angulardisplacement α. It is additionally preferred that the circumferentialbases 143 be the same. Lug 146 is symmetrically shaped, but has anarrower tabular extension 148 than the tabular extensions 150 of theother lugs 142. Directly opposite lug 146 are two adjacent lugs 144,which are canted away from each other to allow lug 146 to be disposedbetween, or interlocking with respect to, the adjacent lugs 144 on anadjacent blank when the blanks are layed out. In addition, lugs 142 areadditionally interlocking with respect to lugs 142 on an adjacent blankon the locations identified with the letter "B". Thus, the containerblanks 140 are preferably arranged upon a scrolled sheet of material 120as described above, with the blanks arranged in two or more rows in atightly spaced configuration. The middle row is offset from the outerrows to allow closer spacing of the blanks 140. In addition, each rowhas the blank lug 146 interlocking with respect to the adjacent blanklugs 144.

Although the invention has been disclosed and described with respect tocertain preferred embodiments, certain variations and modifications mayoccur to those skilled in the art upon reading this specification. Forexample, the invention could be utilized on a cover that is not roundnor which contains a annular channel or an annular rim section. Any suchvariations and modifications are within the purview of the inventionnotwithstanding the defining limitations of the accompanying claims andequivalents thereof.

I claim:
 1. A lug lid for sealing a container having a rim, the lug lidcomprising:a planar surface having a channel on a peripheral edge ofsaid lid; a plurality of lugs projecting from an outer wall of thechannel; one or more of said lugs being asymmetrically shaped relativeto the other lugs; and a plurality of bases formed between adjacentlugs.
 2. The lug lid as in claim 1 wherein said lid has one plane ofsymmetry.
 3. The lug lid as in claim 1 wherein said lid has only oneplane of symmetry.
 4. The lug lid of claim 1 wherein one or more of saidlugs is a male lug and one or more of said bases are female.
 5. The luglid of claim 1 wherein said lid comprises a first half and a second halfwith each half being the mirror image of the other; with the lugs onsaid halves being uniquely shaped.
 6. The lug lid as in claim 1 whereinall of said lugs are asymmetrically shaped.
 7. The lug lid as in claim 1comprising an odd number of lugs.
 8. The lug lid as in claim 1 whereinone or more lugs are canted.
 9. The lug lid of claim 1 wherein said lidis generally disc shaped.
 10. A lug lid comprising:a planar surfacehaving a channel on a peripheral edge of said lid; an odd number of lugsprojecting from an outer wall of the channel with one or more of saidlugs comprising a male lug; and a plurality of circumferential basesformed between adjacent lugs with one or more of said circumferentialbases comprising a female mating gap.
 11. The lug lid as in claim 10wherein said male lug comprises a generally pyramidal shape.
 12. The luglid in claim 10 wherein said female mating gap is generally pyramidallyshaped.
 13. The lug lid as in claim 10 wherein one or more of said lugsare canted away from an adjacent lug.
 14. The lug lid as in claim 10wherein some of said lugs are generally rectangular in shape and withrounded edges.
 15. The lug lid as in claim 10 further including a curlat the end of at least some of the lugs to facilitate removal of the lidfrom the container.
 16. The lug lid as in claim 10 comprising 15 lugs.17. The lug lid as in claim 10 having a circular shape.
 18. A lug lidfor closing an open end of a container comprising a generally planarsurface and a plurality of an odd number of lugs projecting from theperiphery of the generally planar surface, at least one of said lugshaving a different shape than the other said lugs.